variation and similarity in the phonological development of french

York Papers in Linguistics Series 2 ISSN 1758-0315 Issue 11 © The Author, 2011

VARIATION AND SIMILARITY IN THE PHONOLOGICAL DEVELOPMENT OF

FRENCH DIZYGOTIC TWINS: PHONOLOGICAL BOOTSTRAPPING TOWARDS

SEGMENTAL LEARNING?

CATHERINE E. SMITH

Abstract

The few existing studies comparing the language acquisition of twins have shown

contrasting findings with regard to phonological development (Bloch (1921), Leonard et al (1980)). Focussing on the implementation of templates – preferred output patterns

implemented to facilitate production – this study compares the phonological acquisitions

of a pair of twins, as systematisation of the output through templates appears to set the framework for an important shift in language development. Parallel templates are

discussed alongside the observation of a coordinated shift towards segmental learning

despite an initially dissimilar approach to language learning. Evidence from this data

suggests that a form of phonological bootstrapping is taking place between these infants, which leads to further questions regarding the language acquisition of twins in the

longer-term.

1. Introduction

Common universals can be found in the phonological acquisition of different children

acquiring different languages; Smith (1975) identified four universal tendencies of

phonological systematization: consonant harmony, cluster reduction, systematic

simplification and grammatical simplification. Examples of these phenomena can be found in

many longitudinal studies of individual children, such as Macken‟s study of Si, acquiring

Spanish (1979), Smith‟s study of Amahl, acquiring English (1973), and Vihman‟s study of

Raivo, acquiring Estonian (1981). In all of these studies, phonological patterns, or

„templates‟, are implemented to facilitate production in the output, generalizing common

features found in the infants‟ early word forms and causing an infant to adapt words to fit a

familiar output pattern (Vihman and Vihman (in press)). Words are either „selected‟ or

„adapted‟ in line with an infant‟s preferred output patterns; words which already fit the

structure of an infant‟s preferred pattern are „selected‟ for production and are thus produced

accurately, while target words which do not match an infant‟s preferred output pattern are

„adapted‟, changing the structure of the word to match a preferred output pattern. Adapted

words highlight an overriding pattern force of a specific template, allowing an infant to

produce more words, forfeiting output quality for output quantity (Smith (2010)) as

systematic patterns are implemented throughout the lexicon. In later development, infants

begin to shift towards a segment-based approach to word-adaptation, as individual segments

rather than whole words are adapted to facilitate the production of adult word forms (Vihman

(1996)). This highlights an important step in the course of phonological development, as this

allows lexical development on a phoneme-by-phoneme basis, rather than word-by-word

(Smith (2010)).

Templates such as consonant harmony have been found to occur universally (Vihman

(1978)), yet individual infants have been found to differ substantially in their use of templates

(Vihman et al. (1994)), due to factors such as biological constraints, ambient language effects

75 Comparing Variation and Similarity in the Phonological Development of

French Dizygotic Twins: Phonological Bootstrapping Towards

Segmental Learning Procedures

and motor and cognitive factors, as well as the variability in each infant‟s own input.

According to Vihman:

Each child, drawing on his or her unique genetic inheritance to develop vocal resources in the course of the first year of life, influenced or shaped by the speech of the

caretakers, faces and solves a range of word production problems, resulting in an

idiosyncratic first phonological organization.

(Vihman 1993:62; emphases added)

But what does this mean for children who share a genetic inheritance and learning

environment? With the above statement in mind, we could hypothesize that the phonological

development of a set of twins would be similar, or at least show more resemblance than two

unrelated children growing up in different learning environments. Though there are very few

studies observing the phonological development of twins in the current literature, contrasting

reports on this hypothesis can be found in studies by Bloch (1921) and Leonard et al (1980).

Bloch discusses briefly the language development of his twin nephews, whose language is

“identical: as soon as a modification or an acquisition appears in one infant, the other follows

almost immediately” (p. 693, own translation). However, Leonard et al (1980) found that

there is no similarity between twins in the acquisition of phonemes, despite the shared

learning environment and genetic make-up of the infants. This study will consider this

hypothesis further, by focussing on both the similarities and differences in a pair of dizygotic

aɔɛtwins acquiring French in the same environment, where it is fair to assume that they are

receiving an input of the same nature from their caregivers.

2. Methodology

The data used in this study is taken from the CHILDES database (Hunkeler (2005)); a

longitudinal study of dizygotic twins, Camille and Pierre, between the ages of 1;3 and 2;2,

acquiring French as their target language. The data was taken from a set of bi-weekly

sessions, in which the output of each child was transcribed during interaction at home with

the mother, who prompted speech using stimuli such as toys or picture books. Only one twin

was present during each session, ensuring that the infant‟s output was not influenced by

speech from his or her twin. The data was transcribed by the investigator, who was analysing

the early lexical interactions between an infant and his or her mother for his doctoral thesis.

As these twins are not genetically identical, any similarities in their language development

must either reflect fundamental elements of the acquisition of French as a target language, or

„shared idiosyncrasies‟ resulting from a shared learning environment and input.

The majority of tokens produced by both children were nouns relating to everyday objects

such as animals and items of clothing. Due to the nature of the French noun, which rarely

appears without an article, often the children‟s tokens were preceded by an open vowel, either

a/ɔor /ɛcreating what could be interpreted as different realizations for the same word

type (e.g. in Pierre‟s data, „papa‟ daddy had eight different realizations, all with the same

stem, including apapapapaɔpapaand ɛpapa). This „pre-utterance vowel‟ was also

observed in Macken‟s (1979) study of Si acquiring Spanish, and following Macken‟s

interpretation of Si‟s vocabulary, this study will count different instances of vowel + noun

combinations as the same token, as long as the noun itself remains constant.




This data will be used in this study to observe any similarities in the phonological

development of the twins. If an infant‟s first output is “shaped by the speech of the

caretaker”, as Vihman (1993, p.62) proposed, then it is possible to hypothesize that these

twins will indeed share some similarities in their first word forms that go beyond the

universal output patterns identified across all languages (Vihman (1978), Smith (1975)). A

longitudinal study of each infant‟s lexical inventory will identify any recurrent templates in

the output, which will be identified as patterns which are commonly used to adapt output

forms. These will then be compared speculatively to observe whether there are any inherent

similarities between the phonological development of these two infants. The infants‟

development will be compared with regard to both age and output. A comparison of the

infants‟ development with regard to age will give a clear indication of any differences in the

level of their output ability, while a comparison of the two outputs at the 15- and 25-word

points (the points at which the infant produces 15 or 25 words in one recording session,

respectively) will provide a fair comparison of the infants‟ lexicons over the course of their

development.

3. Analysis

Each infant‟s output was observed longitudinally and recurrent patterns in both selected and

adapted word forms were identified. Both infants were found to produce a large proportion of

words with consonant harmony, and both omitted syllables in many forms to produce a

simple CV structure. These patterns correspond with Smith‟s (1975) theory of universal

tendencies in phonological development, reflecting universally common tendencies of

simplifying word forms.

With regard to age, the twins‟ development shows no similarity; Camille produces many

word forms even in her first session, some of which are realized accurately, while Pierre‟s

output progresses more slowly, and retains a relatively low level of accuracy throughout the

study. The twins‟ outputs in the first session at 1;3 can be seen in Table 1, below.




Camille Pierre

auto „car‟ [tu] [tɔ] balle „ball‟ [bab]

ça c’est un poteau „there‟s a post‟ [sa sɛ pɔtɔ] bateau „boat‟ [ba]

c’est ça „that‟s that‟ [sɛ sa] maman „mummy‟ [mama]

chat „cat‟ [ʃa]

coucou „darling‟ [tutu]

maman „mummy‟ [mama]

ours „bear‟ [dɔ]

sauterelle „grasshopper‟ [isøtø]

tchou tchou [train noise] [tɔʃ tɔʃ]

tortue „tortoise‟ [tate], [tata], [toty]

Table 1: Camille and Pierre‟s output forms at 1;3

From Table 1 it is clear that Camille and Pierre differ vastly in their approach to language

production. An analysis of each child‟s individual phonological development will therefore

provide a framework from which the results can be observed, in order to identify any

similarities between the two twins.

3.1. Camille

In her first recording session at 1;3 Camille produces a small yet relatively accurate set of

word forms, as shown in Table 1. Most of these first words are selected, as Camille produces

words which already contain her preferred output patterns, exploiting existing patterns such

as consonant harmony in maman „mummy‟ – mama and tortue „tortoise‟ –tata. Some of

her output forms do not match the target word, however, and are „adapted‟ to fit her

capabilities; syllable deletion is seen in auto „car‟, which is reduced to tɔ, and velar fronting

occurs in coucou „darling‟ as the velar plosive is realized as an alveolar plosive tutu. A

notable occurrence in this first set of words is seen when Camille produces a string of words,

ça c’est un poteau „there‟s a post‟, produced accurately as sa sɛ pɔtɔ. Disyllables are the

most common structure amongst the first words of infants acquiring French, and indeed they

make up the majority of Camille‟s word forms throughout the recordings in this study.

However, though polysyllables are not uncommon in French as they are in English (Vihman

(1991)), this five-syllable word string does suggest that Camille is developing a good

phonological memory and an ability to plan her output at a very early stage in her

development.




Camille continues with a high level of accuracy in her output, and variability in her word

forms is rare, with only 8% of her accumulative word forms produced with any variation by

the 25-word point at 1;8. One of these variable forms marks an important development in

Camille‟s phonological progress: in her third session, at 1;4, Camille produces an almost

accurate realization of the target attention „watch out‟, as sayːt sjɔ However, at 1;6 this

form undergoes syllable deletion to become t sjɔ outlining an instance of regression in the

quality of Camille‟s output. From this point in her development, Camille‟s word forms

become much more systematic, as she develops a set of preferred output patterns and begins

adapting words throughout her inventory to match a set of templates. For example, „palatal

patterns‟ (replacement of certain segments, such as liquids, with the palatal [j], found to be

common in the acquisition of French (Wauquier-Gravelines & Suet-Bouret (2004)), become

much more prevalent, as 31% of Camille‟s output forms contain [j] between 1;6 and 2;0.

These forms are either selected due to an existing [j] in the target word, or adapted using [j]

in place of segments such as land ʀ, as in the examples in Table 2 below:

Replacement of /l/ Replacement of

langue „tongue’ j ɡ (1;8) souris „mouse‟ sɔji(1;4)

de l’eau ‘water‟ djo (1;8) au revoir „good bye‟ aja(1;5)

lampe „lamp‟ ja (1;8) roue ‘wheel‟ ju(1;9)

Table 2: use of /j/ in Camille‟s adapted word forms

In addition to this palatal pattern, over one third of word forms contain a consonant harmony

template in this period; Camille is certainly implementing systematic templates to her word

forms at this point, facilitating her word learning and maximising her output, which is

growing at every recording session.

Just before Camille reaches two years of age, a further development can be seen in her output

forms. At 1;11 she finally produces attention accurately, as at sjɔ , and the appearance of

palatal patterns diminishes as the target consonant [l appears more regularly in her inventory,

both in the correct context – il pleut pas „it‟s not raining‟ iplœpæ (2;0), and incorrectly in

citron „lemon‟ sitlɔ (2;2) – as she starts to over-generalize this newly stable addition in her

phoneme inventory, now replacing target ʀwith linstead of j. At the age of 2;0 it

appears that Camille‟s word forms start to shift towards a more accurate production, as she

begins to adapt individual phonological segments rather than whole words. This change to a

segmental approach to production occurs as her output becomes less systematic and moves

closer to the adult target.

3.2. Pierre

With regard to his output forms and his approach to word learning Pierre‟s phonological

development differs substantially from that of his twin sister; he produces only four words in




his first recording session compared to eleven words in Camille‟s first session (shown in

Table 1). While Camille expands her output very gradually, increasing her production and

reaching the 15-word point at 1;7, Pierre produces an average of only four words per session

for the first six sessions, and then suddenly increases his output three-fold, reaching his 15-

word point a month earlier than Camille, at 1;6. His learning continues in this fashion,

increasing his output suddenly and substantially, until he reaches his 25-word point, almost 3

months later than Camille, at 1;11. He displays a large amount of variability in specific word

forms, especially in sessions where his vocabulary has shown a large increase since the

previous session, as in the following examples in Table 3, taken from the session where he

reaches his 15-word point:

balle ‘ball’ chausson ‘slipper’

[ba] [ʃøʃɔ ]

[baj] [ʃəla]

[bɔ] [ʃø]

[bajaj]

Table 3: variation in the realization of the target words balle and chausson in one recording session.

This variability could reflect instability in Pierre‟s word form representations, showing that

he could be struggling with motor and planning capabilities in his production.

Disregarding the use of the pre-utterance filler, Pierre‟s word forms are all mono- and

disyllabic throughout the recordings, with one exception [apapabrumbrum] – papa brum

brum „daddy brum brum‟ in his final session at 2;2. Alongside a preference for consonant

harmony before the 25-word point, which appears in 25% of word forms, both selected and

adapted, a small number of output constraints are also applied to Pierre‟s output forms. He

selects words with a shared place of articulation, as in pɔm pomme „apple‟ (1;7.27)

anddɔndonne „to give‟ (1;8), or a front-back melody, as in bato bâteau „boat‟ (1;10) and

abɛt bêtes „creatures‟ (1;11), both which contain a bilabial-alveolar melody. When target

forms do not fit either of these preferred patterns, he adapts them using typical processes such

as consonant harmony and syllable deletion, shown in the examples below:

(1) kakacanard ‘duck‟ – consonant harmony (1;6)

(2) bibɔ biberon ‘bib‟ – syllable deletion (1;11).

Though Pierre‟s output could be interpreted as less advanced than that of his twin sister in

terms of both quantity and quality, his capabilities in terms of his articulatory output are not

as restricted as Camille‟s. Whereas Camille systematically implements a palatal template to

deal with the difficult phonemes /l/ and ʀ, Pierre is able to produce both of these in some

instances, seen in Table 4:




l ʀ

vwala voilà „there we go‟ (1;8)

[adlode l’eau „some water‟ (1;7)

ʀɛzɛ raisin „grape‟ (2;0)

ʀɔ rond „round‟ (2;1)

Table 4: instances of landʀin Pierre‟s word inventory

Pierre‟s use of these difficult segments is by no means across-the-board, and he does use

some processes to adapt words which are too challenging, for example:

(3) [baj] balle, „ball‟ (1;6)

(4) [lab ] là-bas, ‘over there‟ (1;8)

(5) [p ja] voilà, „there‟ (1;10)

The lack of a consistent palatal template like Camille‟s for dealing with these segments

reflects an important difference in the twins‟ development, showing that, though the twins

share many of the same phonological challenges in their acquisition of French, they do not

share the same methods for dealing with these. However, the example of voilà at 1;10, above,

shows an occurrence of regression in Pierre‟s word forms when compared with the accurate

realization of voilà in Table 4, vwalaat 1;8. The use of both cluster reduction and palatal

gliding in p jatwo months later shows evidence towards the use of a systematic output

pattern in Pierre‟s vocabulary, though this may not occur across-the-board. This indicates that

Pierre could also be moving towards a segmental approach to word learning, coinciding with

Camille to reach a turning point at 2 years.

4. Identifying Templates in the Infants’ Outputs

Both twins show signs of reaching a „turning point‟ in their phonological development at

around 2 years. Accuracy in the output increases as the twins begin to produce challenging

segments correctly, and previously incorrect or regressive forms move towards a more

accurate realization of the target word. This turning point is best observed through the

example of templates, as they develop, regress and move towards the target production over

time. The templates identified in these infants‟ output do not reflect a restriction in the

production of individual consonants; rather they show restrictions in the production of word

forms. Both twins are able to produce a large variety of phonemes, and no specific phonemes

are completely omitted from either twin‟s inventory. This highlights the existence of a whole-

word approach to production, not on a phonetic level, but on a phonetic level.

4.1. Consonant Harmony Template

The twins each implement two templates which are striking in their resemblance. The first

template to appear in both infants‟ output forms is based on consonant harmony, which is




prevalent in both selected and adapted word forms for both twins. The production of the

fricative ʃ is a challenge for both Camille and Pierre, and the twins use the same consonant

harmony adaptations to overcome the difficulties encountered in production of this phoneme.

Though Camille does not consistently produce ʃ as [s, the use of this phoneme certainly

limited in her output forms, as can be seen in Table 5.

Correct Realizations of /ʃ/ Incorrect Realizations of ʃ/

du chocolat „some chocolate‟ [dyʃojaja] (1;10)

cacher „to hide‟ [taʃe] (1;7)

chercher „to look for‟ [ʃeʃe] (1;8)

chapeau „hat‟ po (1;9)

azø, apo (1;10)

château „castle‟ to(1;8)

Table 5: realization of target ʃ in Camille‟s inventory

Table 5 shows Camille‟s attempts at producing this phoneme as well as word forms which

are adapted to avoid it, and it is clear that it is in some way limited in her output. Upon closer

observation of the distribution of ʃin Camille‟s output forms, it is found that she does

produce this consonant regularly, but only in instances of consonant harmony. There are only

two exceptions to this rule, du chocolat and cacher, seen in Table 5. More examples of this

restriction can be seen in the following word forms, which are very similar in structure, and

Camille is able to take advantage of this by implementing a consonant harmony template

which enables her to adapt all three targets for production:

(6) a. chaussures „shoes‟ - ʃoʃy(1;7 – 1;9)

b. chaussons „slippers‟ -ʃoʃɔ (1;7)

c. chaussettes ‘socks‟ - ʃoʃɔ ʃoʃɛtʃoʃɛʃ(1;6 – 1 ;9)

There is an interesting use of consonant harmony at work in this case, as the consonant on the

unstressed syllable is harmonized, rather than the /s/ on the stressed syllable. However, at 2;0,

chaussures, which was produced consistently as ʃoʃyfor three months, is realized as sosy.

The shift from harmony of the unstressed syllable to harmony of the stressed syllable

indicates that Camille is paying attention to the segmental building blocks of words, even

though the output form remains incorrect. Little by little, this phoneme starts to appear

correctly in some output forms, as she acquires new forms with ʃsuch as aʃjɛ chien, „dog‟

(2;0) and ʃənijchenille, „caterpillar‟ (2;2), as well as updating previously inaccurate forms

with this new phoneme: [to] (1;8) ʃato](2;1) château, „castle‟.

Pierre also appears to struggle with the phoneme ʃin his output, as well as its alveolar

counterpart, /s/. Before 2;0 there are only three realizations of /s/ in his recordings which do

not appear in the context of consonant harmony, while ʃis realized only in situations of




consonant harmony. Though Pierre‟s template is not identical to Camille‟s, he adapts the

same word forms with the same process, to overcome the same phonological restrictions:

(7) a. chaussures „shoes‟ - aføfø (1;8)

b. chaussons „slipper‟ - ʃøʃø (1;4 – 1;10)

c. chaussettes „socks‟ - sosɛt (1;9 – 2;1)

Like his twin sister, Pierre begins to adapt the template as he moves towards a segmental

understanding of word forms; ʃøʃø] becomes sosɔ at 1;10, and aføføis realized as [ʃoʃɔ ] at 2;1. Though the output forms are not the same for both twins in all cases, these examples

suggest that one twin could be copying the other‟s output. Due to the limited appearance of

ʃ and the subsequent adaptations of words containing this phoneme, it is evident that both

infants are struggling with the same output limitations. As one twin begins implementing a

consonant harmony template in order to deal with this phoneme, it could be that the other

twin takes advantage of this to overcome his or her own difficulties. The template first

appears in Pierre‟s word inventory at 1;4, and two months later it is recorded in Camille‟s

output forms, becoming a rather influential template over her whole lexicon in the following

months, as it causes forms to regress through overgeneralization: abeille „bee‟, first realized

accurately as abejat 1;7, is realized as ʃabeʃat 1;8.

Like Camille, Pierre‟s representation of ʃstabilizes at around 2;0, and both ʃand /s/ are

produced accurately more often:

(8) a. chaud „hot‟ ʃ(2;0)

b. chaise „chair‟ ʃɛz (2;1)

c. soleil „sun‟ sɔjɛj(2;1)

d. sous „under‟ su(2;1)

Once again, this suggests that the twins are paying attention to individual segments as their

phonological inventories grow, and they are both reaching this important landmark in their

phonological development at around the same time, though it is clear that their development

is not intrinsically similar in any significant way.

4.2. /m/-Replacement Template

Another limitation which appears in the phonology of both twins involves the phoneme /m/,

and a template is used to adapt some target forms to facilitate production, hereon referred to

as the „/m/-replacement template‟. Though /m/ is produced accurately from the first recording

session (in [mama] maman „mummy‟ for both twins), this phoneme does not appear often in

either twin‟s initial output, and Pierre‟s realizations of /m/ are especially limited, only

appearing correctly in word-initial position in four target words before 2;0:

Camille’s Realization of /m/ Pierre’s Realization of /m/

maman „mummy‟ [mama] (1;3) maman „mummy‟ [mama] (1;3)




main „hand‟ [mɛ ] (1;7)

miaou (cat noise) [mja] (1;7)

Mini [mini] (1;7)

miaou cat noise [mjau] (1 ;8)

main „hand‟ [mɛ ] (1;10)

moi „me‟ [ma] (1;11)

Table 6: realizations of /m/ in each twin‟s lexicon

Pierre continues to implement the /m/-replacement template until the end of the recordings at

2;2. Camille‟s realization of /m/ is also limited, as she only produces four target words with

/m/ before 1;10. However, after this point her use of target /m/ increases rapidly, and she

builds on her existing lexicon with words containing this new stable phoneme. As seen in

Table 6, both infants are able to produce /m/-initial words when the second consonant in the

word is either a nasal or a glide; otherwise, /m/ is replaced with a bilabial consonant with oral

stricture. This suggests that both infants have trouble changing from nasal to oral stricture

across a word, showing evidence towards a whole-word approach to word learning. The /m/-

replacement template adapts words with changing stricture in the target form to facilitate

word production, and is found in both twins‟ output forms. As with the consonant harmony

template, the twins‟ adapted forms are not all identical, but both the phonological challenge

and the process used to overcome this are exactly the same. This template first appears in

Camille‟s lexicon at 1;4.21, when she realizes mouton „sheep‟ as bɔtɔ: Camille Pierre

mouton „sheep‟ bɔtɔ (1;4)

morceau „piece‟ bøzo (2;1)

monsieur „Mr.‟ bəsjø (2;2)

maison „house‟ abɛzɔ (1;11)

manteau „coat‟ pɔto (2;0)

merci „thank you‟ besi (1;7)

maison „house‟ abɛzɔ (2;0)

manteau „coat‟ əpoto (2;2)

merci „thank you‟ [besi] (2;1)

Table 7: use of the /m/-replacement template in each twin‟s lexicon

Table 7 shows all instances of the /m/-replacement template in the recordings. Pierre‟s use of

this template is more consistent, as it appears more densely in his word inventory; more

forms are produced in a shorter space of time. However, the template first appears in

Camille‟s output forms, and as can be seen from the table, identical forms are produced by

both twins, Pierre‟s appearing no more than two recording sessions after Camille first uses

the forms. This could be another example of one twin „borrowing‟ templates from the other;

once again, the twins are meeting the same phonological challenges, and using the same

methods to overcome these challenges.

The use of this template provides another good example of the shift from whole-word

learning to segmental learning at the two-year stage. This is demonstrated in Table 8, below,

where Camille‟s realization of maison „house‟ is shown longitudinally:




1;9 1;10 1;11 2;1 2;2

bɛzɔ

mɛzɔ

amɛzɔ

bazɔ

abɛzɔ

mɛso mɛzɔ

Table 8: development and regression in Camille‟s realizations of maison „house‟

As can be seen in Table 8, Camille is able to produce maison accurately at 1;9, with /m/ in

word-initial position. However, the representation is still unstable, and in the same month her

existing /m/-replacement template is used to adapt this form. In the following month it seems

that maison has resisted adaptation, but by 1;11, two different realizations of maison using

this template prove otherwise. The stressed second syllable of the target word continues to be

produced correctly, however, as the first syllable is adapted to retain oral stricture throughout

the word; Camille is therefore working on words as whole units at this stage. By 2;1, she has

started to move from the whole-word stage to learning individual segments of words, and this

is reflected in her production of maison; the word is no longer adapted with the template, and

the word-initial /m/ is realized correctly, showing that Camille is able to shift from nasal to

oral stricture within a word. However, the stressed syllable is no longer accurate: the fricative

is unvoiced and the vowel is not nasalized, and so as one element of her phonology develops,

another regresses. However, this regression does not last long, as by 2;2 Camille is able to

realize maison as the target form, and by this stage 71% of Camille‟s /m/-initial targets are

produced correctly.

4.3. From Whole Words to Segments

Systematization of the lexicon through the implementation of templates provides a way for

the developing infant to practice using words, despite lacking some of the necessary tools to

do so. As Thelen and Smith (1994) explained in their theory of cognitive development,

dynamic systems theory, action is a necessary part of development, and in the case of

linguistic development, „action‟ is manifested in word production. Infants select templates

based on their own abilities and phonological preferences, and adapt whole word forms to

meet their output constraints, as seen in this study, as the production of fricative consonants

or oral stricture across whole word forms constrain the output of both Camille and Pierre. As

an infant‟s phonemic lexicon grows, his constraints upon the whole word diminish, and he

begins attending to the individual segments which make up the word. As seen in Table 8, this

often causes previously accurate segments to regress as attention shifts to different units in

the word, but as this example also shows, a regression in accuracy signals development, and

accuracy will follow as a result of this.

At 2 years, both Camille and Pierre appear to reach a turning point in their development

which marks the shift from whole word learning to segmental learning. Their routes to

language in the preceding months show no similarities in terms of ability; the infants

approach language learning in different ways throughout the recordings, and their strengths

and weaknesses differed as a result of this; Camille‟s lexicon grew steadily over the recording

sessions, while Pierre‟s remained constant before the occurrence of an apparent vocabulary




„spurt‟, for example. While Camille approached word use carefully, paying attention to detail

and accuracy without producing any variability in her forms, Pierre‟s approach was

comparatively haphazard, with many variable word forms and no real systematic approach to

the more difficult phonemes. With this in mind, their joint arrival at segmental learning at

around 2 years is surprising, though this is by no means an absolute in their production, as

development is still very much on-going at this point. However, this raises questions about

the relationship between the language development of a pair of twins: at first so different in

nature, how can two infants reach segmental learning at the same time, gathering along the

way the same set of templates and even some identical output forms? Further investigation

into the development of twins is needed if this question is to be answered, both to identify

any similarities in output forms, and to pinpoint any parallels in the landmark developments

that infants make on their route into language.

5. Discussion

The findings from this study support the contrasting observations of both Bloch (1921) and

Leonard et al (1980). In line with Leonard et al‟s findings, the twins do not acquire the same

phonological units in the same order; in fact they do not even show signs of using the same

approaches to phonological development. However, Bloch‟s observation of one twin

following the other‟s phonological acquisitions is found in the data, as the twins implement

the same template which causes them to produce some identical output forms, and no doubt a

larger set of recordings would back up this observation even further.

It is unsurprising that the twins are encountering the same phonological difficulties in their

outputs. Indeed, the four universal tendencies of phonological systematization (Smith (1975))

arise from a selection of common output constraints encountered during language

development, which result in the same universal output patterns. Thus the appearance of

consonant harmony in order to deal with a change in manner of articulation, or even the use

of oral harmony to avoid changing vocal stricture within a word cannot be considered as

unusual, for twins as well as for unrelated infants. However, questions remain regarding the

identical forms found in both twins‟ outputs; are these identical due to both twins

implementing their shared templates on the same words, or is one twin imitating the other‟s

output forms? As different output forms for the same target words occur in each infant‟s

lexicon as a result of these templates, it can be deduced that both templates are active in each

infant‟s phonological development. However, the influence that the twins have on each

other‟s input and output with regard to these templates cannot be judged from this data, and

more recordings would be needed to track the full extent of these findings. It seems that a

form of phonological „bootstrapping‟ is at work here, as one twin uses the other twin‟s

phonology to overcome his or her parallel phonological challenges. Even with a complete set

of data it would not necessarily be possible to answer the question of which came first: the

template or the output form – did the infant borrow a template, producing the same output

forms as a result of this, or did the infant borrow an output form, which went on to become a

template as a phonological hurdle became easier to overcome?

As for similarities in the phonological development of these twins, while these identical

templates do not suggest any genetic influence on the twins‟ language developments, they do

highlight the influence of the learning environment and the interactions within that

environment on an infant‟s unfolding phonological system. Furthermore, the underlying

phonological challenges reflect similarities in the twins‟ overall production capabilities,




which is backed up further by evidence of a coordinated shift from whole word learning to

segmental learning despite a vast difference in the initial approach to language acquisition.

All in all, these findings raise some important questions regarding the language development

of twins, especially those concerning the nature versus nurture dichotomy, which remains a

contended issue in the world of language acquisition. Similarities found in this study could be

down to inherent similarities in the infants‟ development due to genetic inheritance, though

the findings lean towards the influence from a shared learning environment. After all, the

learning environment of a pair of twins differs significantly from that of non-twin infants,

both in terms of attention from the caregiver as well as input, which will consist largely of the

other twin‟s output forms. All of these criteria must be considered when observing any form

of twins‟ development, and without a large sample of both twin and non-twin infants,

hypotheses regarding similarities are unlikely to be proven. However, the similarities found

in this longitudinal observation of twins‟ output forms provides a basis for further

investigation, as the implementation of templates sets up an infant for his continuing

phonological development, and so the use of identical templates in the output could have

some important effects on further language production.

6. References

BLOCH, O. (1921). Les premiers stades du langage de l‟enfant [The first stages in an Infant‟s

Language]. Journal de psychologie [Journal of Psychology].

EDWARDS, J., BECKMAN, M. E., AND MUNSON, B. (2004). The interaction between vocabulary

size and phonotactic probability effects on children‟s production accuracy and fluency

in nonword repetition. Journal of Speech, Language, and Hearing Research, 47, 421–

436.

HUNKELER, H. (2005). Aspects of the evolution of the early lexicon in the interactions

mother-child: Case study of two dizygotic twin children between 15 and 26 months.

University of Rouen.

LEONARD, L. B., NEWHOFF, M. & MESALAM, L. (1980) Individual differences in early child

phonology. Applied Psycholinguistics, 1. 7-30.

MACKEN, M. (1979) Developmental Reorganization of Phonology: A Hierarchy of Basic

Units of Acquisition. Lingua, 49. 11-49.

SMITH, C. E. (2010). Exploring the Role of Systematization in Phonological Development: A

Dynamic Systems Perspective. MA Dissertation: University of York.

SMITH, N. V. (1973). The Acquisition of Phonology: A Case Study. Cambridge: Cambridge

University Press.

SMITH, N. V. (1975) Universal Tendencies in the Child‟s Acquisition of Phonology. In B.

Lust and C. Foley (eds.), First Language Acquisition: The Essential Readings. London:

Blackwell.

THELEN, E. AND SMITH, L. B. (1994). A Dynamic Systems Approach to the Development of

Cognition and Action. Cambridge: MIT Press.

VIHMAN, M. M. (1978). Consonant Harmony: Its Scope and Function in Child Language. In

J. Greenberg, C.A. Ferguson & E.A. Moravcsik (eds.), Universals of Human Language,

2. Stanford, CA: Stanford University Press.

VIHMAN, M. M. (1981). Phonology and the development of the lexicon. Journal of Child

Language, 8, 239–264.




VIHMAN, M. M. (1991). Ontogeny of Phonetic Gestures: Speech Production. In I.G.

Mattingley and M. Studdert-Kennedy (eds.) Modularity and the Motor Theory of

Speech Perception. New Jersey: Lawrence Erlbaum Associates Inc.

VIHMAN, M. M. (1993) Variable paths to early word production. Journal of Phonetics, 21.

61-82.

VIHMAN, M. M., KAY, E., DE BOYSSON-BARDIES, B., DURRAND, C. AND SUNDBERG, U.

(1994). External Sources of Individual Differences? A Cross-Linguistic Analysis of the

Phonetics of Mother‟s Speech to 1-Year-Old Children. Developmental Psychology, 30,

5, 651-662.

VIHMAN, M. M. AND CROFT, W. (2007). Phonological development: toward a „radical‟

templatic phonology. Linguistics, 44-5, 683-725.

VIHMAN, M. M. AND VIHMAN, V-A. (in press). From first words to segments: A case study in

phonological development. In E. V. Clark and I. Arnon (eds.) Title TBA, Trends in

Language Acquisition Research. John Benjamins.

WAUQUIER-GRAVELINES, S. AND SUET-BOURET, D. (2004). Acquisition des attaques

syllabiques et „palatal patterns‟. Pourquoi yod ? [Aquisition of Syllabic Onsets and

„Palatal Patterns‟. Why yod?]‘Phonologie’ conférence [‘Phonology’ Conference].

Orléans, France. 3rd June 2004. Université de Nantes.

Acknowledgements

With thanks to Marilyn Vihman, Daniel Laing and Edward Haynes.

Catherine Smith

email: [email protected]

variation and similarity in the phonological development of french

Documents